辉长岩在冲击加载下的相变及物态方程  

Shock-induced phase transformation and equation of state of gabbro

作　　者：地力夏提[1] 黄晓葛[1] 陈祖安[1] 刘福生[2] 袁贤昊[2] 白武明[1] 

机构地区：[1]中国科学院地质与地球物理研究所地球深部研究重点实验室,北京100029 [2]西南交通大学高温高压物理研究所,成都610031

出　　处：《地球物理学报》2014年第9期2826-2832,共7页Chinese Journal of Geophysics

基　　金：国家自然科学基金(41174074;41174073);中国科学院知识创新工程重要方向项目(KZCX2-EW-118)资助

摘　　要：岩石相变关系对限定地球内部物质成分和动力学关系有着重要意义.利用光探针在14~39 GPa压力区间对热压烧结的辉长岩样品进行了冲击波加载实验.从16 GPa开始,D-u线斜率发生明显变化,说明样品内发生了相变.利用原始的Hugoniot曲线结合地震波状态方程(Seismic Equation of State)得到了Birch-Murnaghan型的等熵压缩线和相变能.结合前人的实验结果,得到了辉长岩的Gr(u|¨)neisen参数yo,约为2.3.计算得到相变后的矿物集合体在零压下的密度为3.41 g·cm^(-3).根据以上参数分析得出,在此压力段辉长岩相变主要由长石的分解反应和石英的高压相变控制.Hugoniot data for the gabbro sample which was generated by hot-pressing from powder was obtained by means of light probe in the pressure range from 14 to 39 GPa.The discontinuity in the D-u curve indicates a phase transformation at 16 GPa.Utilizing raw hugoniot data coupled with seismic equation of state,we obtained a Birch-Murnaghan type adiabat.Compared with previous experimental data,the Griuneisen parameter was calculated through available hugoniot data of diabase.Self-consistent calculation of Birch-Murnaghan type adiabat gave the mineral assemblages＂ density of 3.41 g·cm-3 that is in good agreement with that of the discomposition reaction of albite.

关 键 词：辉长岩 冲击波 相变 Birch-Murnaghan物态方程 

分 类 号：P313[天文地球—固体地球物理学]